Effect of geometrical parameters on the evaporative heat transfer and pressure drop of R-134a flowing in dimpled tubes

被引：0
作者：
Kanit Aroonrat
Lazarus Godson Asirvatham
Ahmet Selim Dalkılıç
Omid Mahian
Ho Seon Ahn
Somchai Wongwises
机构：
[1] King Mongkut’s University of Technology Thonburi,Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Lab (FUTURE), Department of Mechanical Engineering, Faculty of Engineering
[2] Department of Mechanical Engineering,Heat and Thermodynamics Division, Department of Mechanical Engineering
[3] Karunya Institute of Technology and Sciences,School of Chemical Engineering and Technology
[4] Yildiz Technical University,Renewable Energy and Micro/Nano Sciences Lab., Department of Mechanical Engineering
[5] Xi’an Jiaotong University,Department of Mechanical Engineering
[6] Ferdowsi University of Mashhad,undefined
[7] Incheon National University,undefined
[8] National Science and Technology Development Agency (NSTDA),undefined
来源：
Heat and Mass Transfer | 2021年 / 57卷
关键词：
Evaporation; Heat transfer; Pressure drop; Dimpled tube;
D O I：
暂无
中图分类号：
学科分类号：
摘要：
An investigation was experimentally performed to explore the influence of geometrical parameters on the evaporative heat transfer coefficient and pressure drop of R-134a in dimpled tubes. The test sections were the counter-flow tube-in-tube heat exchanger, where the refrigerant was evaporated in the inner tube and hot water flows in the annulus. Seven dimpled tubes with various helical pitches (p), dimpled pitches (z), and dimpled depths (e) were used as the test tubes. The test runs were carried out over mass fluxes of 300, 400, and 500 kg/m2s; heat fluxes of 20, 25, and 30 kW/m2; and evaporating temperatures of 7, 10, and 13 °C. The results show the heat transfer enhancement factor (HF) and pressure drop penalty factor (PF) increase with a rise in e and a decrease in p and z. The HF and PF range between 1.03–1.7 and 1.76–9.00, respectively. The correlations for predicting the Nusselt number and the friction factor of R-134a during evaporation in dimpled tubes are proposed.
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页码：465 / 479
页数：14
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